1. Field of the Invention
The present invention relates to a process for preparing ceramic powder and, more particularly, to a process for preparing ceramic powder in a core-shell structure.
2. Description of the Related Art
As ceramic electronic parts have recently been developed so as to make their sizes smaller and smaller and to make their quality higher and higher, a variety of materials have also been developed so as to catch up with such development. Under such technical background, ceramic powder having a core-shell structure is now being highlighted as a material for ceramic electronic parts.
Such ceramic powder having a core-shell structure is configured in such a manner that it comprises a highly crystalline core portion and a shell portion formed on and around the core portion and composed of a different composition material. The such ceramic powder can smooth temperature features of a ceramic condenser when it is used as a dielectric material.
The ceramic powder with such a core-shell structure can be produced, for instance, by admixing ceramic powder with an additive and firing the resulting mixture at a high temperature to thereby subject it to solid phase reaction to allow the additive to be formed on and around surfaces of the ceramic powder.
Further, it is favorable if ceramic powder having a core-shell structure could be produced from highly crystalline ceramic powder because such a highly crystalline ceramic powder has good electrical features such as dielectric constant and so on. The highly crystalline ceramic powder, however, has the drawbacks that it is so low in reactivity that a considerably high temperature is required to cause an occurrence of solid phase reaction, resulting to a rise in manufacturing cost.
On the other hand, a low-crystalline ceramic powder can produce ceramic powder with a core-shell structure because it can readily be subjected to solid phase reaction by firing it at a lower temperature. Such a low-crystalline ceramic powder, however, presents the drawbacks that ceramic electronic parts prepared therefrom may result in poor electrical and mechanical characteristics.